Congrats on making Gold!
You will maintain your 2014 status that you achieved for 2015. Anything over the Gold plateau will rollover - anything over 50 nights up to the Platinum level of 75 points will be rolled over to help with hitting the goal for the next year.
Enjoy the increased benefits!
I was actually just looking at my numbers for the year. This might help...
Rollover nights only count once. Any rollover nights you had last year will not rollover again. Chances are that you'll begin the new year with no rollover nights (unless you end up really close to achieiving Platinum and had a fairly small number of rollover nights to begin this year). There are a couple of simlar threads discussing this issue (see More Like This) in the margin to the right.
Hope that helps a little.